moderators have removed the method for supporting me from the top post in this topic, (aff link for some very good virtual private servers provider).
But you can find a method if you wish to express your gratitude in Valkyrie NPC or in readme.txt
Same as this one (with few limitations) https://irowiki.org/wiki/IRO_Servers_Comparison
settings you can find in conf/battle/player.conf

is the game server working? Must work 3 console window (login, char, and map servers) and all of them must NOT have any "ERROR" messages in the console.
Also, you must see a green flag, and you need to use ONLY files inside the package, do not mix it with your own client (if you have any from any other server)
There are a lot of updates since the 02 March 2017. The current version includes a lot of fixes and a lot of problems solved since the beginning of the last 2 years.
So, let me think about how you can upgrade everything for yourself with minimal efforts and downloads. If I will be in your position I would do next:
First of all, need to realize what do I have, what version of emulator and client (you said you have 2017 one). How to do this? To be clear if you have no experience it's hard if you have experience - it's easy by checking which hash your emulator and which commits you to see in the git log and from what date (you can do it with git log command) all that you need to see just dates. These "dates" need to determine what exactly SQL patches do you need to apply to your current game database for not losing your current gameplay experience
Second, I will copy-paste just for backup purposes ALL files what I have
Then, I will download just two folders from the first post: (01_emulator, and 02_client_side) Why? Because these folders interconnected, emulator configured for client version, client version configured for the emulator. They can't be different, they must be in pairs.
Now, I will extract 01_emulator somewhere (what I just did download). And will run openserver what I had earlier.
After this need to open phpmyadmin from openserver and import missing SQL upgrades from emulator_folder/sql/upgrades but what exactly upgrades apply? This is an interesting question, and the answer can be found in #1 that why we answered this question earlier. As you see here: https://github.com/rathena/rathena/tree/master/sql-files/upgrades these .sql patches have the next name structure: upgrade_DATE_DATABASE.sql Where date = date where this upgrade released and DATABASE where need to apply this upgrade. You have two databases one game database, and one log database. You can find it in your phpmyadmin.
Before touching anything, you need to export with phpmyadmin ALL of your databases (you can do it easily) just to make sure that you will NOT lose your data what you have now in your MySQL server database. How to do that? Select table -> export -> and you will get files called <your_database_name.sql>, do it for main and for logs databases, or for all that you see just for backup purposes.
Now it the hardest thing. Need to apply .sql upgrades patches (which modify your game database what you have right now) since the date when the last upgrade patch released up to the latest patch in STRICT order, one by one.
For example, you said you have 02 March 2017 version of the package. That means next:
1. look here: https://github.com/rathena/rathena/tree/master/sql-files/upgrades
You see next:
That means you have emulator after the march, and probably to make everything perfect I already have an actual database in the package released on March 02 2017 with all patches above by default before the 02 March 2017. That means right now 28 June 2019, and developers created next patches:
upgrade_20170327.sql and up to upgrade_20190309.sql which means I need to apply them 1 by 1, first 20170327, second 20170417.sql, third 20170509, and so on. This is a very quick process with phpmyadmin (you need to select IMPORT) and select a SQL patch and click import, one second - and your database now will be patched and will have a different structure from this patch.
As you see some files have names: "upgrade_20180705_LOGS.sql" that means these patches must be applied TOO but to _log database what you can find in your MySQL server with phpmyadmin. The same logic as with main patches, but all of them applied 1 by 1 too but to log database. Easy is not it?
If you will do it, and will apply all patches (you can apply 1 patch only once, after that your whole database structure will be changed, and you will not be able to apply the same patch twice or even can corrupt database easy) So always keep backups of your database in phpmyadmin (export feature) and do not worry to remove whole database and re-import your database again and repeat everything if you failed.
8. Now, after applying your patches to your database from the folder of emulator what you just downloaded above (01_emulator) you have the same data structure in your game database like emulator expect to see. Now both game-database (in MySQL server) emulator and MySQL will know about the data what is it and how to work with it. That means - emulator will work now just fine, what you just downloaded. Otherwise, if you forgot to apply some of the patches, or did a mistake, you will see SQL errors in your servers.
9. Now the last step, you need to get clean kRO game client somewhere (if you have one good, but I recommend to download full kRO client from the link above)
Just download, install, extract.
10. Now extract files from 02_client_files folder and copy-paste them as you did to your clean kRO folder
11. Try to connect, everything must be smooth and you must see your OLD data on upgraded emulator (which is released precompiled) and client which configured for emulator and vise verse.
12. Open openserver (green flag), emulator, client. And enjoy.
This guide can be used as a guide for upgrading your emulators if you have an old version of the package and wish to upgrade to the latest released version on the website but do not know what to do. Just replace 02 March 2017 to your date what you have on your hand and enable the brain to think and do like I said above in the game (abstract and detailed) and you will not fail.

SQL? item_db.sql? Open Server -> Green Flag -> Click on Green Flag -> Advanced -> Phpmyadmin
Login: root
Pass: empty field
Press Enter
After that, you will open an sql connection to your MySQL server where all databases stored.
And with UI you can easily import, delete, remove whatever you want with any databases as you wish from phpmyadmin
This is not a problem, this is just informative messages about what is going on on the server. You can easily turn them off inside /conf/map_athena or char_athena or login_athena conf files. (separate setting per server)
I think there are many videos about how to add custom items. Also, there are many guides on how to add customs.
My package just a portable thing which not requires configuration out the box just to make the emulator run, nothing more.
For example https://github.com/rathena/rathena/wiki/Custom-Items
You must know, that exe (client) is 2018 years old in this package (new one), not ""old one". So you need always for your custom items guides where you will see ItemInfo.lub or iteminfo.lua (it's the same filename but with different extensions).
https://rathena.org/board/topic/108766-about-adding-custom-items-with-new-client-new-way/

After a lot of testing, the guide is NOT actual for 2019 MSBuild tools. Because the size of the community build tools is about 4.6GB, while the WHOLE installation of the complete package required for rAthena is just 5.6GB or 6.6GB with IDE. This is not worth it.
If you wish to save your internet traffic and disk space, I have for you a piece of bad news...
The only way is to use old 2017 build tools and downloading them from somewhere...
An alternative method will be cygwin like packages, but they are not compatible with rathena only source code after last changes with epoll changes, yaml crap libs inside include dirs which implemented not properly and not only. All of these things make impossible to use 300mb archive with compiler and cygwin for compiling the emulator (see my another topic in Projects and Concepts).
What to do?
or install buildtools for VS2017
or install buildtools for VS2015
or install Visual Studio 2013
The size will be less than in latest VS 2019
compile.cmd for VS Buildtools 2019
@Echo OFF
Echo "Building solution/project file using batch file"
SET PATH=C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\MSBuild\Current\Bin
SET SolutionPath=%~dp0\rAthena.sln
Echo Start Time - %Time%
MSbuild.exe %SolutionPath% /p:PlatformToolset=v142 /m
Echo End Time - %Time%
Set /p Wait=Build Process Completed...
Just copy-paste it to compile.cmd if you're using buildtools 2019, and copy-paste compile.cmd to your rathena folder, and run, it will compile the code without VS Studio Community 2019 IDE

You don't need to download 12.3gb of data, around 3GB or even 1.5GB by using MSBuild Tools https://docs.microsoft.com/en-us/cpp/build/msbuild-visual-cpp?view=vs-2019
Or:
About the upgrade:
I explained in the post about the update how to do it, and also whole theory several times, sorry I will not explain it another 10 times the same thing which is not changed for years
Second: updated kRO is not really what you need, yes you can download it, but only optionally, the pack will work with old kRO client just fine
Third: in the last 01 June 2019 update changed only emulator part (and recompiled) so maximum what needs to download up to 300mb instead of 3GB or 12.3GB of data. Download, extract, play (if you played before on 2019 April 27 update)

Do not follow old guides for adding items. If you do not see in the guide ItemInfo.lua - skip the guide. There are historically two versions of clients <= 20120410 which has one file structure and before big changes how items structures information stored inside the game client, and after 20120410 up to now, with small changes inside ItemInfo.lua.
Find better a guides with ItemInfo.lua and without idnumrestable or like that

Usually, it is enough to make fonts readable and follow your system settings. Otherwise, use NEMO to increase font size by applying a font-size increased patch which can break your whole client alignment of the elements or even do many worst things.